Congress rejected a plea by the Bush administration yesterday over a resolution officially recognising as genocide the deportation and massacre of Armenians in the last days of the Ottoman empire.

George Bush warned of the negative repercussions should Congress use the word genocide to describe the killing of an estimated 1.5 million Armenians and their exile.

"This resolution is not the right response to these historic mass killings, and its passage would do great harm to our relations with a key ally in Nato and in the global war on terror," Mr Bush said.

But hours later the House foreign affairs committee voted by 27 to 21 in favour of the resolution. The measure now goes to the full House for a vote.

Condoleezza Rice, the secretary of state, had warned the resolution could set back Middle East peace prospects. Its passage could also put US soldiers at risk in Iraq, Robert Gates, the secretary of defence, said, warning that America risked losing important supply routes. About 70% of air cargo for Iraq goes through Turkey.

But the measure has strong support in the Democratic-controlled House, where more than half of members have signed on as co-sponsors, including the speaker, Nancy Pelosi. About half of the Senate has co-sponsored the measure.

The resolution calls on Mr Bush to use the word genocide during the commemoration of the killings each April. Turkey has spent millions on dissuading western governments from labelling the events of 1915-7 a genocide. The Turkish military cancelled defence contracts with France last year when its national assembly voted to make denial of the genocide a crime. Turkey does not deny that many Armenians were killed, but claims the deaths were the result of widespread fighting.